Police say at least nine suspected illegal immigrants have died and six more were injured when the van they were traveling in rolled over in a South Texas border town.

Palmview police Cmdr. Lenny Sanchez says is it not clear what caused the accident around 10:30 p.m. Tuesday on U.S. 83.

Sanchez says the van was carrying 19 people from Mexico and that he believes they were all in the U.S. illegally. He says two people who fled the wreck are in custody and two more are on the loose.

Police are trying to determine if the driver is among the dead.

Sanchez says three women have been treated and released to immigration authorities. Three men remain hospitalized Wednesday. Sanchez has no details on their conditions.